Previously, CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons) were used as a refrigerant substance, but they may destroy an ozone layer. Then, HFCs (hydrofluorocarbons), more specifically HFC-125 (pentafluoroethane), HFC-32 (difluoromethane) and the like become to be used as an alternate refrigerant substance, widely. However, HFC-125 and HFC-32 have a strong potential for heat-trapping, so that there is concern that the diffusion thereof may affect global warming. Although they are recovered from disposed apparatuses to prevent diffusion and thus global warming, it is impossible to recover all of them. Also, diffusion by leakage can not be disregarded. Use of CO2 or hydrocarbon-based compounds as another alternate refrigerant substance is considered, but they have many problems in its efficiency and safety.
Recently, as an alternate refrigerant substance which is able to solve such problems, 1,1,1,2,3-pentafluoropropene (CF3CF═CHF, hereinafter also referred to as “HFC-1225ye”) and 1,1,1,2-tetrafluoropropene (CF3CF═CH2, hereinafter also referred to as “HFC-1234yf”) come to the front, both of which are HFCs of olefins having a low global warming potential.
These fluorine-containing olefins can be produced by a dehydrohalogenation reaction of corresponding fluorine-containing halogenated alkanes (see, for example, Patent Citations 1-3).
Patent Citation 1: JP 3158440 B2
Patent Citation 2: US 2007/0179324 A1
Patent Citation 3: WO 2007/056194 A1
Patent Citation 4: JP 3412165 B2
Patent Citation 5: JP 2000-34237 A